1 schedule column has a bold fond?

[laurensV9CRL]

Hellow

has anyone an idea why somethimes my colum fonds has a checkmark like this 

and sometimes this

an dhow can i choose between both? because when it is the second screenshot my hole collum is bold but when it is the first screenshot its only my title

[mhiserZFHXS]

You don't choose which mark it is. The mark is based on what you have made bold.

[Mike.FORM]

If you select a whole column by clicking on the 'A' and change the font it will change the body and header font type and show a checkmark.

If you select just the header and change the font to something different than the body font and then select the whole column again by clicking the 'A' it will show a dash or filled box indicating that the value varies within the selection.

The 2 left images show the column being all bold font. The right 2 images show the header is not bold and the body is bold.